Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B19/00—Machines, plants or systems, using evaporation of a refrigerant but without recovery of the vapour
  • F25B19/005—Machines, plants or systems, using evaporation of a refrigerant but without recovery of the vapour the refrigerant being a liquefied gas
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D3/00—Devices using other cold materials; Devices using cold-storage bodies
  • F25D3/10—Devices using other cold materials; Devices using cold-storage bodies using liquefied gases, e.g. liquid air
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2500/00—Problems to be solved
  • F25B2500/01—Geometry problems, e.g. for reducing size
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
  • F25B2700/04—Refrigerant level
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F6/00—Superconducting magnets; Superconducting coils
  • H01F6/04—Cooling

Definitions

• the present invention generally relates to the field of cryogenic cooling installations of superconducting devices and, more particularly, relates to improvements made to such installations comprising:
• cryogenic fluid supply conduit functionally associated with the reservoir for its supply of cryogenic fluid
• a cryogenic fluid supply control valve disposed in said supply conduit
• a conventional arrangement of an installation covered by the invention is illustrated in Figure 1 of the accompanying drawing.
• a reservoir 1 contains a biphasic cryogenic fluid whose liquid phase 2 is surmounted by a vapor phase 3.
• a superconducting device 4 is immersed in the liquid phase 2.
• a cryogenic fluid supply conduit 5 is connected to the reservoir 1 and a control valve 6, incorporated in the supply duct 5, makes it possible to control the supply of cryogenic fluid into the tank 1.
• An outlet manifold 7 is provided for the evacuation of the cryogenic fluid vaporized by the thermal loads of the system.
• a level gauge 8 for example functionally associated with the control valve 6, to detect the level of filling of the tank 1 with cryogenic fluid in the liquid phase and controlling the control valve 6.
• the thermal loads of the system are absorbed by partial vaporization of the cryogenic liquid, by acting on the latent heat of vaporization thereof.
• the vaporized cryogenic fluid is discharged through the outlet manifold 7, while cryogenic fluid in the liquid state is supplied as needed under the control of the level gauge 8 and the control valve 6 so that the device superconductor 2 remains permanently immersed.
• cryogenic fluid in the liquid state in contact with which the device must be maintained disappears rapidly and completely. both because of its vaporization due to the increase of the thermal load and because of its high flow turbulent entrainment in the outlet manifold.
• the return to a cooling of the device and the recovery of a state of superconductivity requires that cryogenic fluid in the liquid state is fed back into the tank.
• This new supply of liquid cryogenic fluid not only requires time, but above all requires a supply of fluid that is expensive.
• the main purpose of the invention is to propose an improved arrangement for an installation of the type in question which makes it possible to ensure its correct and reliable operation in the presence of normal thermal conditions, but which, in the presence of abnormal thermal conditions, allows a re-immersion faster device and faster recovery of the state of superconductivity and also avoids the loss of liquid cryogenic fluid initially present in the tank and therefore allows a substantial saving in cryogenic fluid.
• the invention proposes an installation as mentioned in the preamble which is characterized, being arranged according to the invention, in that it further comprises:
• auxiliary reservoir being arranged with respect to the main reservoir and being dimensioned so as to be able to receive at least a large part of the cryogenic fluid present in liquid form in the main reservoir,
• liquid cryogenic fluid in the presence of rapid heating of the superconducting device, liquid cryogenic fluid is indeed vaporized, but its discharge into the outlet manifold of the main tank is strongly braked by the restriction means.
• the pressure of the vaporized cryogenic fluid increases in the reservoir and at least a portion of the cryogenic fluid in the liquid state present in the main reservoir is discharged, under the action of this pressure of the vaporized cryogenic fluid, into the reservoir.
• auxiliary tank This liquid cryogenic fluid present in the auxiliary reservoir flows again by gravity towards the main reservoir when the pressure of the vaporized fluid decreases therein.
• cryogenic fluid discharged that is reintroduced into the main tank, but this filling of the main tank intervenes without delay as soon as the thermal overload has disappeared and this automatically by gravity.
• the amount of cryogenic fluid which passed through the restriction means during this process and which has disappeared remains relatively small and has nothing to compare with the large volume of fluid, both vaporized and liquid, which was evacuated in a conventional installation under the same circumstances.
• auxiliary reservoir In order that the auxiliary reservoir can be made in a relatively compact form, it is advantageous that it be arranged substantially higher than the main reservoir, so that only a small amount of liquid cryogenic fluid is contained therein under conditions normal thermal.
• means for detecting the level of the liquid cryogenic fluid are arranged in the auxiliary tank.
• the restriction means comprise a restriction, or, in a more elaborate embodiment, that they comprise an externally controlled valve.
• FIG. 1 is a schematic view illustrating a conventional installation covered by the invention
• FIG. 2A is a schematic view illustrating an installation of the type of. Figure 1 improved according to the invention, shown under normal thermal conditions;
• Figure 2B is a schematic view illustrating the installation of Figure 2A in the presence of a significant and rapid change in thermal conditions
• FIG. 3 is a schematic view similar to that of Figure 2A showing an interesting variant of the embodiment of the installation according to the invention.
• FIG. 2A the installation arranged in accordance with the invention incorporates the elements shown in FIG. 1 with, in addition, a second reservoir or auxiliary reservoir 9.
• a . hydrostatic connection duct 10 is interposed between the respective bottoms of the main tank 1 and auxiliary tank 9.
• the cryogenic fluid supply pipe 5, with its control valve 6, is connected to the auxiliary tank 9 and the level gauge 8 is installed in the auxiliary tank 9.
• the auxiliary tank 9 is also equipped with an outlet manifold 7b, while the outlet manifold 7a of the main tank 1 is provided with restriction means 11. As illustrated in FIG. 2A, the two manifolds 7a and 7b can meet , downstream of the restriction means 11, into a single collector 7.
• the auxiliary reservoir 9 is arranged with respect to the main reservoir 1 and is dimensioned so as to receive at least a large part of the cryogenic fluid present in liquid form in the main reservoir 1. The auxiliary reservoir 9 is shifted upwards with respect to the main tank 1.
• cryogenic fluid in liquid form is received in the auxiliary tank 9 and the transfer gas losses are evacuated directly by the collector 7b.
• the collector 7b Only cryogen in the pure liquid state is delivered by gravity to the main tank 1 via the connecting pipe 10 of large size, with a negligible pressure drop.
• the mass flow rate of vaporized cryogen m n r m m generated in the cryogenic liquid 2 by a thermal load in normal operation is discharged through the manifold 7a through the restriction means 11.
• auxiliary reservoir 9 is such that the liquid 12 which is present there is surmounted by a volume 13 free (that is to say containing vaporized cryogen) relatively large corresponding at least to the most of the liquid cryogen present in the main tank 1.
• the hot device 4 which is no longer immersed at least for the most part in the cryogenic liquid, is thermally decoupled from it.
• the cryogenic liquid By its reflux from the main tank to the auxiliary tank, the cryogenic liquid is spared and it is not discharged to the outside and lost as is the case in conventional installations such as that of Figure 1.
• the pressure drop in the restriction means 11 As the flow of gas in the manifold 7a decreases, the pressure drop in the restriction means 11 also decreases and thus the difference in the liquid levels in the two reservoirs is reduced until it reaches a point where the transfer takes place. liquid from the auxiliary tank 9 to the main tank 1 can recover. Then the auxiliary tank 9 discharges by gravity into the main tank 1 to return to the normal situation shown in Figure 2A, with the device 4 again completely immersed in the cryogenic liquid.
• a turbulent gas flow in the outlet manifold 7a and the restriction means 11 one can write:
• the outlet manifold 7a and the restriction means 11 are appropriately sized according to the properties of the cryogenic fluid in its liquid and gaseous phases, and also as a function of the thermal loads provided during normal operation.
• the restriction means 11 comprise a fixed restriction 14 inserted in the conduit 7a.
• the restriction means 11 may comprise, instead of the aforementioned simple fixed restriction 14, an externally actuated valve 15 as illustrated in FIG. 3. Such an arrangement makes it possible, in particular, to increase the efficiency of the reflux of the liquid cryogen and to control the restarting of the transfer of the liquid cryogen to the main tank 1 and the resumption of cooling of the superconducting device 4.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)
• Containers, Films, And Cooling For Superconductive Devices (AREA)
• Superconductors And Manufacturing Methods Therefor (AREA)

Applications Claiming Priority (2)

Publications (2)

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• 2005
  • 2005-01-27 FR FR0500861A patent/FR2881216B1/fr not_active Expired - Fee Related
• 2006
  • 2006-01-24 EP EP06709162A patent/EP1842013B1/de not_active Expired - Lifetime
  • 2006-01-24 US US11/814,539 patent/US8069679B2/en not_active Expired - Fee Related
  • 2006-01-24 DE DE602006002248T patent/DE602006002248D1/de not_active Expired - Lifetime
  • 2006-01-24 AT AT06709162T patent/ATE404829T1/de not_active IP Right Cessation
  • 2006-01-24 WO PCT/FR2006/000163 patent/WO2006079711A1/fr not_active Ceased

Non-Patent Citations (1)

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